The present invention disclosed herein relates to a substrate treatment apparatus and a substrate treatment method, and more particularly, to a substrate treatment apparatus and method capable of uniformly treating a bottom surface of a substrate.
Generally, a plurality of thin layers such as a polycrystal layer, oxide layer, a nitride layer and a metal layer are deposited on a wafer used as a substrate in fabrication processes of semiconductor devices. A photoresist layer is coated on the thin layers. A pattern formed on a photomask using an exposure process is transferred onto the photoresist layer. Thereafter, a desired pattern is formed on the wafer by an etching process.
Unnecessary impurities such as various thin layers and photoresists remain on a bottom surface of the wafer performed by the above-described processes. The thin layers and photoresists acting as particles pollute equipment during subsequent processes. Thus, an etching process is required to remove unnecessary impurity layers such as various thin layers and photoresists remaining on the bottom surface of the wafer.
A substrate treatment apparatus for etching the bottom surface of the substrate includes an injection head injecting a chemical solution to the bottom surface of the rotating wafer. The injection head includes a body disposed in a center region of a lower portion of the wafer and an injection member extended from the body to an edge region of the wafer. A plurality of injection openings are formed on the injection member. The chemical solution is injected through the openings to the bottom surface of the wafer. The chemical solution injected to the bottom surface of the wafer flows toward the edge region of the wafer due to rotation of the wafer to remove the impurities remaining on the bottom surface of the wafer.
However, a conventional substrate treatment apparatus has following problems.
The chemical solution supplied to the injection member flows from an inside of the injection member corresponding to the center region of the wafer to an outside of the injection member corresponding to the edge region of the wafer. The chemical solution is first injected through the injection openings formed on the inside of the injection member and is then injected through the injection openings formed on the outside of the injection member.
As the injection openings are distant from the center region of the wafer, an internal pressure decreases because the chemical solution is injected through the injection openings. Therefore, it is difficult that a flow and injection pressure of the chemical solution injected at the injection openings formed on the outside of the injection member are exactly controlled due to pressure drop. Also, although a non-processed area increases progressively further from the center region of the wafer, an exact control of the flow and the injection pressure is not difficult. Therefore, the impurity layers formed in the edge region of the wafer are not satisfactorily etched, thereby decreasing an etching uniformity of the bottom surface of the wafer.